Ocean platform drill string top drive and drilling fluid pump combined testing device and design method

Abstract

The application discloses a kind of marine platform drill string top drive and drilling fluid pump combined testing device and design method, device includes torque simulation device, pressure reduction simulation device and simulation drill pipe;Torque simulation device adopts star-shaped shovel type water resistance structure, pressure reduction simulation device adopts deformable rubber throttle sleeve driven by hydraulic pressure to realize stepless regulation of flow passage.Design method is divided into two parts of torque and pressure drop: torque part is corrected torque coefficient by fitting structural parameters, and iteration is matched target output torque;Pressure drop part establishes flow-pressure closed loop model, simulates and fits the relationship between structural parameters and hydraulic pressure, synchronously checks that contact stress meets sealing and strength requirement, finally through multiple regression model, the optimal structural parameters are calculated inversely.The beneficial effects of the application are: it realizes the functions of large torque, small space and underwater stepless regulation, etc.The top drive torque and drilling fluid pump pressure drop combined test can be completed synchronously, and it is suitable for various marine drilling conditions, with high test precision, reliable structure and stable regulation and control.

Description

Technical Field

[0001] This invention relates to the field of offshore oil and gas drilling and production equipment technology, and more specifically to a test device and design method for a combined test of a drill string top drive and a drilling fluid pump for an offshore platform. Background Technology

[0002] Since 2023, the offshore drilling platform market has continued to expand, with a stable compound annual growth rate of over 10%. The industry scale has rapidly increased, and the demand for performance testing of offshore drilling platform equipment has also grown accordingly. To objectively test the performance of the top drive of offshore platforms and reduce its impact on on-site production operations, it is crucial to conduct specialized testing of the top drive and drilling fluid pumps.

[0003] In offshore oil and gas drilling and production operations, the top drive is the core execution equipment of the drilling system, and its performance and safety status directly determine the drilling efficiency; the drilling fluid pump is a key high-pressure fluid transportation device, and its operational stability is related to the drilling safety and continuity of operations.

[0004] Currently, research on key technologies such as safe commissioning and hydraulic rotation loading of offshore drilling platforms is relatively scarce, and there is a lack of mature and reliable testing equipment and solutions in the market. In particular, given the special needs of offshore drilling for "high torque, small space, and stepless underwater adjustment", the development of a drill bit pressure drop and hydraulic torque adjustment device with dynamic adjustment capabilities and a compact structure has become an urgent need for the upgrading of offshore oil and gas drilling and production equipment.

[0005] The device requires overcoming two major technical challenges, which are key bottlenecks that existing technologies have not yet fully resolved: First, there is a contradiction between high torque output and small turning radius structure. This device requires the achievement of ultra-high torque output under the constraint of small radius, which requires the design of "slender ratio optimization + blade-type water resistance structure". The blade is the core component for generating water resistance torque, and its parameter design has multiple constraints. In terms of shape, straight blades have uniform water resistance distribution but low torque, spiral blades can increase torque but are difficult to manufacture, and blades with closed edges can enhance water resistance but increase flow field disturbance. In terms of size, the blade spacing also needs to match the flow velocity.

[0006] Secondly, for stepless regulation of fluid pressure within the pipe, the valve body must withstand seawater corrosion when the pressure drop control device is in operation. The lifespan of the seals is only 1 / 3 of that of similar land-based products. If a hydraulic design is adopted, the hydraulic lines and high-speed rotating bodies are prone to entanglement, requiring complex rotary joints. Furthermore, the underwater valve body must withstand extremely large pressure differentials and extend its lifespan to at least 5,000 cycles to achieve interference-free pressure drop transmission. If mechanical transmission is adopted, there is pressure drop hysteresis due to contact gaps, which needs to be eliminated by adjusting the preload. At the same time, the underwater force sensor needs to be integrated into the pressure drop transmission path to avoid structural deformation errors. If electromechanical transmission is adopted, the deep-sea seal will make it difficult for the motor to dissipate heat, and the power cable is prone to fatigue breakage during high-speed rotation. High-voltage electricity needs to be transmitted through an underwater umbilical cable, and an explosion-proof motor and water-cooling jacket are required to ensure that the temperature is ≤60℃ during continuous operation. At the same time, a power failure protection mechanism should be designed to prevent sudden power failure from causing uncontrolled pressure drop.

[0007] In conclusion, it is now urgent to develop relevant technologies and equipment to break through existing technological bottlenecks and provide new technical paths and solutions for offshore drilling operations. Summary of the Invention

[0008] This invention overcomes the shortcomings of the prior art and provides a combined testing device and design method for offshore platform drill string top drive and drilling fluid pump.

[0009] The joint testing device for the drill string top drive and drilling fluid pump of offshore platform includes: a torque simulation device, a pressure reduction simulation device, and a simulated drill pipe; The torque simulation device is nested on the simulated drill rod. With the simulated drill rod as the central axis, multiple bucket-shaped water resistance structures are evenly arranged along the circumference of the simulated drill rod to form a star-shaped water resistance torque output structure. The simulated drilling fluid channel inside the pressure drop simulation device is connected to the drilling fluid pump through the drilling fluid channel inside the simulated drill pipe, and a hydraulic tightening mechanism is provided on the simulated drilling fluid channel.

[0010] The torque simulation device includes blades, a top plate, and side plates. The blades are arranged in a star-shaped pattern along the simulated drill rod. The two side plates are respectively set on the left and right sides of the blades and fixedly connected to form a bucket-type water resistance structure. The top plate is fixedly provided on the free end side of the blades.

[0011] The design method for a torque simulation device includes the following specific steps: S1. Determine the design conditions and structural constraints of the torque simulation device; S2. Calculate the maximum diameter D of the torque simulation device and the length h of the torque adjustment device using the torque calculation formula. The torque calculation formula is as follows: in, Target output torque, in N·m; n, operating speed, in r / min; ρ, seawater density, in kg / m³. 3 g is the acceleration due to gravity, with units of m / s². 2 ; d is the drill pipe diameter, in meters; D is the maximum diameter of the torque simulation device, in meters; h is the length of the torque adjustment device, in meters; The torque coefficient is initially determined and taken as 0.279; S3, set the setting spacing x1, side plate length x2, blade length x3 and top plate length x4 of the torque adjustment device; S4. Substitute x1, x2, x3, D and x4 into the preset fitting formula to obtain the influence factors A of the setting spacing of the torque adjustment device, B of the side plate length, C of the blade length, E of the maximum diameter of the torque simulation device and F of the top plate length. S5. Calculate the corrected torque coefficient based on the influence factors obtained in S4. The formula for calculating the torque coefficient correction is as follows: in, This is the corrected torque coefficient; The attenuation coefficient for the influence of each factor on torque coupling is 0.76. S6. Calculate the actual output torque Actual output torque The calculation formula is as follows: S7, Compare with actual output torque With target output torque The data parameters are adjusted, including the maximum diameter D of the torque simulation device, the length h of the torque adjustment device, the setting spacing x1 of the torque adjustment device, the side plate length x2, the blade length x3, and the top plate length x4. S3-S6 are repeated until the actual output torque is achieved. With target output torque Once the difference in the data parameters meets the set threshold requirements, the process ends and the acquired parameter data is output.

[0012] In S7, the equal torque equivalence formula is used to calculate the relationship between the maximum diameter D of the torque simulation device and the length h of the torque adjustment device. The specific equal torque equivalence formula is as follows. in, The length of the torque adjustment device before adjustment is in meters. D1 is the length of the adjusted torque regulating device, in meters; D2 is the maximum diameter of the torque simulation device before adjustment, in meters; D1 is the maximum diameter of the adjusted torque simulation device, in meters; D2 is the drill rod diameter before adjustment, in meters; D3 is the drill rod diameter after adjustment, in meters.

[0013] The specific steps for obtaining the preset fitting formula in S4 include: S41. Select the structural parameters: the setting spacing x1 of the torque adjustment device, the side plate length x2, the blade length x3, the top plate length x4, and the maximum diameter D of the torque simulation device; S42. Using the controlled variable method, multiple working conditions are set for each parameter, and torque data T under each working condition is collected through simulation. S43. Set a set of fixed structural parameters as the benchmark working condition, calculate the influence rate of torque corresponding to each set of working conditions, and unify the quantitative benchmark of the influence rate of each parameter. S44. Based on the discrete data of the values ​​of each group of structural parameters and the corresponding relative influence rate of torque, a nonlinear fitting method is used to fit the data, transforming the discrete data into a continuous mathematical formula, and obtaining the torque influence factors A, B, C, E, and F corresponding to each structural parameter, thus completing the establishment of the preset fitting formula.

[0014] The pressure reduction simulation device includes: a deformable rubber throttling sleeve inside the pressure reduction shell, which serves as a simulated drilling fluid channel; the drilling fluid inlet of the pressure reduction shell is connected to the drilling fluid outlet; the drilling fluid inlet of the pressure reduction shell is connected to the drilling fluid channel of the simulated drill pipe; the drilling fluid outlet is connected to the drilling fluid pool through a pipeline; and a hydraulic expansion bladder is nested on the outer wall of the deformable rubber throttling sleeve, which is connected to a hydraulic pipeline installed on the pressure reduction shell.

[0015] The design method for a step-down simulation device includes the following specific steps: A1. Determine the basic parameters, including the parameter range of the working flow rate Q and the hydraulic oil pressure. Parameter range, target pressure drop Flow coefficient C and drilling fluid density ρ; A2. Based on the working flow rate Q and hydraulic oil pressure determined in A1 The parameter range is selected by choosing multiple sets of flow rate Q and hydraulic oil pressure. As input conditions, simulation calculations are performed on each set of conditions to obtain the corresponding simulated drilling fluid channel diameter d; A3. Based on the data obtained in A2, a function for simulating the drilling fluid channel diameter is obtained by fitting the data. ; A4. Simulate drilling fluid channel diameter function Substitute into the pressure drop formula to establish a closed-loop model. Closed-loop model for, ; A5, will be implemented through a closed-loop model. Calculated pressure drop vs. target pressure drop Compare the data and determine whether the error pressure drop meets the threshold. If it meets the threshold, proceed to step A6. If it does not meet the threshold, return to step A2 to adjust the data and reacquire the simulated drilling fluid channel diameter d. A6. Simulate the drilling fluid channel's effective area A, deformable rubber throttle sleeve length L, and hydraulic expansion bladder thickness by changing the structural parameters respectively. Thickness of deformable rubber throttling sleeve Simulate and fit various parameters with hydraulic oil pressure The relationship between the deformable rubber throttle sleeve and the simulated drill pipe was determined, and the maximum contact stress P between them under various working conditions was calculated. J Verify whether the contact stress meets the sealing requirements; A7. Constructing a multiple regression model ; A8. Based on the target pressure drop The workload Q is obtained through a closed-loop model. and the function of simulating drilling fluid channel diameter Calculate hydraulic oil pressure The calculated hydraulic oil pressure Substituting the values ​​into a multiple regression model, we obtain the simulated drilling fluid channel area A, the deformable rubber throttle sleeve length L, and the hydraulic expansion bladder thickness. Thickness of deformable rubber throttling sleeve The parameter data.

[0016] The beneficial effects of this invention are as follows: This invention employs a modular design, effectively resolving the contradiction between high torque output and small turning radius structures in existing technologies. It also simplifies design complexity and ensures product reliability. Users can freely design the dimensional parameters of the torque adjustment device based on the structural design formula provided in this invention, according to actual testing needs, thereby achieving multi-level torque output. This greatly expands the flexibility of testing scenarios and can accurately meet the performance testing requirements of different offshore drilling platform equipment under various working conditions.

[0017] To achieve this beneficial effect, this invention has conducted in-depth research on the rotational characteristics of the torque regulating device in seawater, systematically analyzed the influence of key factors such as device structure and fluid resistance on torque output, and derived a scientific and reasonable structural design formula through theoretical derivation, providing solid theoretical support for the implementation of modular design. At the same time, it ensures the quality stability and operational reliability of the torque regulating device, which is conducive to the large-scale production, promotion and application of the product.

[0018] Building upon this foundation, the present invention also achieves continuous adjustment of the pressure drop, effectively overcoming the technical bottleneck of stepless adjustment of fluid pressure within existing pipes, and improving test adaptability and operational stability. Driven by hydraulic oil, the present invention enables continuous and stable control of the flow channel diameter, eliminating the need for frequent replacement of fixed throttling components and significantly improving operational convenience. This design significantly broadens the applicability and working condition compatibility of the device, meeting the pressure drop requirements corresponding to various drill bit waterhole diameters, and can be widely applied to mud pump performance testing under different complex working conditions such as simulating shallow drilling, deep wells, and shale gas wells.

[0019] Meanwhile, through the coordinated operation of the high-strength outer shell and internal structure, combined with multiple sealing designs, the sealing performance and structural stability of the device are effectively improved, ensuring long-term stable operation of the system in the high-pressure, high-flow-rate marine drilling test environment, and solving the problems of short life of seals and easy failure under high pressure in existing technologies.

[0020] Furthermore, through theoretical modeling and finite element simulation analysis, this invention clarifies the formula for the influence of key parameters on voltage drop, making voltage drop control more precise and reliable, fully meeting the simulation test requirements in different scenarios, and further improving the accuracy of test data. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the torque simulation device of the present invention; Figure 2 This is a schematic diagram illustrating the use of the voltage reduction simulation device of the present invention; Figure 3 This is a cross-sectional view of the voltage reduction simulation device of the present invention; In the diagram: 1. Torque simulation device; 101. Blade; 102. Top plate; 103. Side plate; 2. Pressure reduction simulation device; 201. Pressure reduction shell; 202. Deformable rubber throttling sleeve; 203. Drilling fluid inlet; 204. Drilling fluid outlet; 205. Hydraulic expansion bladder; 206. Hydraulic pipeline; 3. Simulated drill pipe; 301. Drilling fluid channel. Detailed Implementation

[0022] Example The offshore platform drill string top drive and drilling fluid pump joint testing device includes: torque simulation device 1, pressure reduction simulation device 2 and simulated drill pipe 3; The torque simulation device 1 is nested on the simulated drill rod 3. The torque simulation device 1 has multiple bucket-type water resistance structures evenly arranged around the simulated drill rod 3 with the simulated drill rod 3 as the central axis, forming a star-shaped water resistance torque output structure. The simulated drilling fluid channel 301 set in the pressure drop simulation device is connected to the drilling fluid pump through the simulated drill pipe 3. The simulated drilling fluid channel 301 is equipped with a hydraulic tightening mechanism.

[0023] like Figure 1 As shown, the torque simulation device 1 includes: blades 101, top plate 102 and side plate 103. The blades 101 are arranged in a star shape along the simulated drill rod 3. The two side plates 103 are respectively arranged on the left and right sides of the blades 101 and fixedly connected to form a bucket-type water resistance structure. The top plate 102 is fixedly provided on the free end side of the blades 101.

[0024] The design method of the step-down simulation device 2 includes the following specific steps: S1. Determine the design conditions and structural constraints of the torque simulation device.

[0025] The design operating data includes the target output torque. Operating speed n, seawater density ρ, gravitational acceleration g, and drill pipe diameter d.

[0026] The structural constraints are the maximum extreme values ​​of the maximum diameter D of the torque simulation device and the maximum extreme values ​​of the length h of the torque adjustment device.

[0027] S2. Calculate the maximum diameter D of the torque simulation device and the length h of the torque adjustment device using the torque calculation formula.

[0028] S3. Set the setting spacing x1, side plate length x2, blade length x3, and top plate length x4 of the torque adjustment device.

[0029] S4. Calculate each influencing factor using the set values.

[0030] Furthermore, the specific steps for obtaining the preset fitting formula in S4 include: S41. Select the structural parameters: the setting spacing x1 of the torque adjustment device, the side plate length x2, the blade length x3, the top plate length x4, and the maximum diameter D of the torque simulation device; S42. Using the controlled variable method, multiple working conditions are set for each parameter, and torque data T under each working condition is collected through simulation. S43. Set a set of fixed structural parameters as the benchmark working condition, calculate the influence rate of torque corresponding to each set of working conditions, and unify the quantitative benchmark of the influence rate of each parameter. S44. Based on the discrete data of the values ​​of each group of structural parameters and the corresponding relative influence rate of torque, a nonlinear fitting method is used to fit the data, transforming the discrete data into a continuous mathematical formula, and obtaining the torque influence factors A, B, C, E, and F corresponding to each structural parameter, thus completing the establishment of the preset fitting formula.

[0031] This embodiment provides a table showing the influence of the torque adjustment device's setting interval on torque, as detailed below: Table 1. Influence of torque adjustment device spacing x1 on torque. Based on the data in Table 1, the most suitable fitting method is selected. In this embodiment, the specific fitting formula for the influence factor is as follows: S5. Calculate the corrected torque coefficient based on the influence factors obtained in S4. .

[0032] S6. Calculate the actual output torque .

[0033] S7, Compare with actual output torque With target output torque The data parameters are adjusted, including the maximum diameter D of the torque simulation device, the length h of the torque adjustment device, the setting spacing x1 of the torque adjustment device, the side plate length x2, the blade length x3, and the top plate length x4. S3-S6 are repeated until the actual output torque is achieved. With target output torque Once the difference in the data parameters meets the set threshold requirements, the process ends and the acquired parameter data is output.

[0034] Preferably, when the actual output torque With target output torque If the deviation of the data parameters exceeds 5%, it needs to be readjusted.

[0035] like Figure 2 and Figure 3 As shown, the pressure reduction simulation device 2 includes: a deformable rubber throttling sleeve 202 is provided inside the pressure reduction housing 201. The deformable rubber throttling sleeve 202 serves as a simulated drilling fluid channel 301. The drilling fluid inlet 203 of the pressure reduction housing 201 is connected to the drilling fluid outlet 204. The drilling fluid inlet 203 of the pressure reduction housing 201 is connected to the drilling fluid channel 301 of the simulated drill pipe 3. The drilling fluid outlet 204 is connected to the drilling fluid pool through a pipeline. A hydraulic expansion bladder 205 is nested on the outer wall of the deformable rubber throttling sleeve 202. The hydraulic expansion bladder 205 is connected to the hydraulic pipeline 206 provided on the pressure reduction housing 201.

[0036] The design method for a step-down simulation device includes the following specific steps: A1. Determine the basic parameters, including the parameter range of the working flow rate Q and the hydraulic oil pressure. Parameter range, target pressure drop Flow coefficient C and drilling fluid density ρ.

[0037] A2. Based on the working flow rate Q and hydraulic oil pressure determined in A1 The parameter range is selected by choosing multiple sets of flow rate Q and hydraulic oil pressure. As input conditions, simulation calculations are performed on each set of conditions to obtain the corresponding simulated drilling fluid channel diameter d.

[0038] The simulated drilling fluid channel diameter d is the equivalent diameter d of the deformable rubber throttling sleeve.

[0039] A3. Based on the data obtained in A2, a function for simulating the drilling fluid channel diameter is obtained by fitting the data. .

[0040] A4. Simulate drilling fluid channel diameter function Substitute into the pressure drop formula to establish a closed-loop model. Closed-loop model for, ; A5, will be implemented through a closed-loop model. Calculated pressure drop vs. target pressure drop Compare the data to determine if the error pressure drop meets the threshold. If it does, proceed to step A6. If it does not meet the threshold, return to step A2 to adjust the data and reacquire the simulated drilling fluid channel diameter d.

[0041] Preferably, the acceptable standard for pressure drop difference is less than or equal to 3%.

[0042] A6. Simulate the drilling fluid channel's effective area A, deformable rubber throttle sleeve length L, and hydraulic expansion bladder thickness by changing the structural parameters respectively. Thickness of deformable rubber throttling sleeve Simulate and fit various parameters with hydraulic oil pressure The relationship between the deformable rubber throttle sleeve and the simulated drill pipe was calculated; and the maximum contact stress P between the deformable rubber throttle sleeve and the simulated drill pipe under various working conditions was calculated. J Verify whether the contact stress meets the sealing requirements.

[0043] This embodiment provides the length L of the deformable rubber throttling sleeve and the maximum contact stress P. J+ The relationship table is as follows: Table 2 Relationship between the length of deformable rubber throttling sleeve and maximum contact stress The specific fitting formula in this embodiment is as follows.

[0044] Hydraulic oil pressure The fitting formula for the relationship between the simulated drilling fluid channel area A and the actual working area A is: The length L of the deformable rubber throttle sleeve and the hydraulic oil pressure The fitting formula for the relationship is: Deformable rubber throttling sleeve thickness With hydraulic oil pressure The fitting formula for the relationship is: Hydraulic expansion bladder thickness With hydraulic oil pressure The fitting formula for the relationship is: Using polynomial interpolation, the formula is fitted: A7. Constructing a multiple regression model .

[0045] A7 uses a multiple quadratic regression equation to obtain a unified formula to describe the simulated drilling fluid channel area A, the deformable rubber throttle sleeve length L, and the hydraulic expansion bladder thickness. Thickness of deformable rubber throttling sleeve hydraulic oil pressure The specific effects of this embodiment are as follows: A8. Based on the target pressure drop The workload Q is obtained through a closed-loop model. and the function of simulating drilling fluid channel diameter Calculate hydraulic oil pressure The calculated hydraulic oil pressure Substituting the values ​​into a multiple regression model, we obtain the simulated drilling fluid channel area A, the deformable rubber throttle sleeve length L, and the hydraulic expansion bladder thickness. Thickness of deformable rubber throttling sleeve The parameter data.

[0046] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A combined testing device for offshore platform drill string top drive and drilling fluid pump, characterized in that, include: Torque simulation device, pressure reduction simulation device, and simulated drill pipe; The torque simulation device is nested on the simulated drill rod. With the simulated drill rod as the central axis, multiple bucket-shaped water resistance structures are evenly arranged along the circumference of the simulated drill rod to form a star-shaped water resistance torque output structure. The simulated drilling fluid channel inside the pressure drop simulation device is connected to the drilling fluid pump through the drilling fluid channel inside the simulated drill pipe, and a hydraulic tightening mechanism is provided on the simulated drilling fluid channel.

2. The combined testing device for the drill string top drive and drilling fluid pump of an offshore platform according to claim 1, characterized in that, The torque simulation device includes blades, a top plate, and side plates. The blades are arranged in a star-shaped pattern along the simulated drill rod. The two side plates are respectively set on the left and right sides of the blades and fixedly connected to form a bucket-type water resistance structure. The top plate is fixedly provided on the free end side of the blades.

3. The design method of the torque simulation device in the combined testing device for the drill string top drive and drilling fluid pump of the offshore platform as described in claim 1 or 2, characterized in that, The specific steps include: S1. Determine the design conditions and structural constraints of the torque simulation device; S2. Calculate the maximum diameter D of the torque simulation device and the length h of the torque adjustment device using the torque calculation formula. The torque calculation formula is as follows: in, Target output torque, in N·m; n, operating speed, in r / min; ρ, seawater density, in kg / m³. 3 g is the acceleration due to gravity, with units of m / s². 2 ; d is the drill pipe diameter, in meters; D is the maximum diameter of the torque simulation device, in meters; h is the length of the torque adjustment device, in meters; The torque coefficient is initially determined and taken as 0.279; S3, set the setting spacing x1, side plate length x2, blade length x3 and top plate length x4 of the torque adjustment device; S4. Substitute x1, x2, x3, D and x4 into the preset fitting formula to obtain the influence factors A of the setting spacing of the torque adjustment device, B of the side plate length, C of the blade length, E of the maximum diameter of the torque simulation device and F of the top plate length. S5. Calculate the corrected torque coefficient based on the influence factors obtained in S4. The formula for calculating the torque coefficient correction is as follows: in, This is the corrected torque coefficient; The attenuation coefficient for the influence of each factor on torque coupling is 0.

76. S6. Calculate the actual output torque Actual output torque The calculation formula is as follows: S7, Compare with actual output torque With target output torque The data parameters are adjusted, including the maximum diameter D of the torque simulation device, the length h of the torque adjustment device, the setting spacing x1 of the torque adjustment device, the side plate length x2, the blade length x3, and the top plate length x4. S3-S6 are repeated until the actual output torque is achieved. With target output torque Once the difference in the data parameters meets the set threshold requirements, the process ends and the acquired parameter data is output.

4. The design method of the torque simulation device in the combined testing device for the drill string top drive and drilling fluid pump of the offshore platform according to claim 3, characterized in that: In S7, the equal torque equivalence formula is used to calculate the relationship between the maximum diameter D of the torque simulation device and the length h of the torque adjustment device. The specific equal torque equivalence formula is as follows. in, The length of the torque adjustment device before adjustment is in meters. D1 is the length of the adjusted torque regulating device, in meters; D2 is the maximum diameter of the torque simulation device before adjustment, in meters; D1 is the maximum diameter of the adjusted torque simulation device, in meters; D2 is the drill rod diameter before adjustment, in meters; D3 is the drill rod diameter after adjustment, in meters.

5. The design method of the torque simulation device in the combined testing device for the drill string top drive and drilling fluid pump of an offshore platform according to claim 3, characterized in that, The specific steps for obtaining the preset fitting formula in S4 include: S41. Select the structural parameters: the setting spacing x1 of the torque adjustment device, the side plate length x2, the blade length x3, the top plate length x4, and the maximum diameter D of the torque simulation device; S42. Using the controlled variable method, multiple working conditions are set for each parameter, and torque data T under each working condition is collected through simulation. S43. Set a set of fixed structural parameters as the benchmark working condition, calculate the influence rate of torque corresponding to each set of working conditions, and unify the quantitative benchmark of the influence rate of each parameter. S44. Based on the discrete data of the values ​​of each group of structural parameters and the corresponding relative influence rate of torque, a nonlinear fitting method is used to fit the data, transforming the discrete data into a continuous mathematical formula, and obtaining the torque influence factors A, B, C, E, and F corresponding to each structural parameter, thus completing the establishment of the preset fitting formula.

6. The combined testing device for the drill string top drive and drilling fluid pump of an offshore platform according to claim 1, characterized in that, The pressure reduction simulation device includes: a deformable rubber throttling sleeve inside the pressure reduction shell, which serves as a simulated drilling fluid channel; the drilling fluid inlet of the pressure reduction shell is connected to the drilling fluid outlet; the drilling fluid inlet of the pressure reduction shell is connected to the drilling fluid channel of the simulated drill pipe; the drilling fluid outlet is connected to the drilling fluid pool through a pipeline; and a hydraulic expansion bladder is nested on the outer wall of the deformable rubber throttling sleeve, which is connected to a hydraulic pipeline installed on the pressure reduction shell.

7. The design method of the pressure reduction simulation device in the combined testing device for the drill string top drive and drilling fluid pump of the offshore platform as described in claim 1 or 6, characterized in that, The specific steps include: A1. Determine the basic parameters, including the parameter range of the working flow rate Q and the hydraulic oil pressure. Parameter range, target pressure drop Flow coefficient C and drilling fluid density ρ; A2. Based on the working flow rate Q and hydraulic oil pressure determined in A1 The parameter range is selected by choosing multiple sets of flow rate Q and hydraulic oil pressure. As input conditions, simulation calculations are performed on each set of conditions to obtain the corresponding simulated drilling fluid channel diameter d; A3. Based on the data obtained in A2, a function for simulating the drilling fluid channel diameter is obtained by fitting the data. ; A4. Simulate drilling fluid channel diameter function Substitute into the pressure drop formula to establish a closed-loop model. Closed-loop model for, ； A5, will be implemented through a closed-loop model. Calculated pressure drop vs. target pressure drop Compare the data and determine whether the error pressure drop meets the threshold. If it meets the threshold, proceed to step A6. If it does not meet the threshold, return to step A2 to adjust the data and reacquire the simulated drilling fluid channel diameter d. A6. Simulate the drilling fluid channel's effective area A, deformable rubber throttle sleeve length L, and hydraulic expansion bladder thickness by changing the structural parameters respectively. Thickness of deformable rubber throttling sleeve Simulate and fit various parameters with hydraulic oil pressure The relationship between the deformable rubber throttle sleeve and the simulated drill pipe was determined, and the maximum contact stress P between them under various working conditions was calculated. J Verify whether the contact stress meets the sealing requirements; A7. Constructing a multiple regression model ; A8. Based on the target pressure drop The workload Q is obtained through a closed-loop model. and the function of simulating drilling fluid channel diameter Calculate hydraulic oil pressure The calculated hydraulic oil pressure Substituting the values ​​into a multiple regression model, we obtain the simulated drilling fluid channel area A, the deformable rubber throttle sleeve length L, and the hydraulic expansion bladder thickness. Thickness of deformable rubber throttling sleeve The parameter data.

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